Component configured to stiffen an electric motor assembly

ABSTRACT

An apparatus includes a first component and a second component. The second component is located at a first position. The second component includes a first connection to the first component. The first position and the first connection are configured to stiffen an electric motor assembly.

BACKGROUND

An electric motor may use stators, magnets, and/or coils to rotate anobject. For example, a motor may rotate data storage disks used in adisk drive storage device. The data storage disks may be rotated at highspeeds during operation using the stators, magnets, and/or coils. Forexample, magnets and coils may interact with a stator to cause rotationof the disks relative to the stator.

In some cases, electric motors are manufactured with increasinglyreduced sizes. For example, in order to reduce the size of a disk drivestorage device, the size of various components of the disk drive storagedevice may be reduced. Such components may include the electric motor,stator, magnets, coils, and motor parts. The precision at which thestators, magnets, coils and motor parts are manufactured may affect theacoustical properties and performance of the electric motor.

SUMMARY

An apparatus includes a first component and a second component. Thesecond component is located at a first position. The second componentincludes a first connection to the first component. The first positionand the first connection are configured to stiffen an electric motorassembly.

These and other aspects and features of embodiments may be betterunderstood with reference to the following drawings, description, andappended claims.

BRIEF DESCRIPTION OF DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements.

FIG. 1 provides a plan view of a hard disk drive including a printedcircuit board assembly (PCBa) attached to a base, according to oneaspect of the present embodiments.

FIG. 2 provides a plan view of a hard disk drive including a PCBalaminated to a base, according to one aspect of the present embodiments.

FIG. 3 provides a plan view of a hard disk drive including a connectorblock attached to a cover, according to one aspect of the presentembodiments.

FIG. 4 provides a plan view of a hard disk drive including a firstcomponent attached to a second component, according to one aspect of thepresent embodiments.

FIG. 5 provides a plan view of a hard disk drive including an additionalcomponent configured to reduce vibration of the hard disk drive,according to one aspect of the present embodiments.

FIG. 6 provides a side view of a hard disk drive including a structurefor adjusting vibration, according to one aspect of the presentembodiments.

FIG. 7 shows an exemplary flow diagram for determining a componentconfiguration, according to one aspect of the present embodiments.

DETAILED DESCRIPTION

Before various embodiments are described in greater detail, it should beunderstood that the embodiments are not limited to the particularembodiments described and/or illustrated herein, as elements in suchembodiments may vary. It should likewise be understood that a particularembodiment described and/or illustrated herein has elements which may bereadily separated from the particular embodiment and optionally combinedwith any of several other embodiments or substituted for elements in anyof several other embodiments described herein.

It should also be understood that the terminology used herein is for thepurpose of describing embodiments, and the terminology is not intendedto be limiting. Unless indicated otherwise, ordinal numbers (e.g.,first, second, third, etc.) are used to distinguish or identifydifferent elements or steps in a group of elements or steps, and do notsupply a serial or numerical limitation on the elements or steps of theembodiments thereof. For example, “first,” “second,” and “third”elements or steps need not necessarily appear in that order, and theembodiments thereof need not necessarily be limited to three elements orsteps. It should also be understood that, unless indicated otherwise,any labels such as “left,” “right,” “front,” “back,” “top,” “bottom,”“forward,” “reverse,” “clockwise,” “counter clockwise,” “up,” “down,” orother similar terms such as “upper,” “lower,” “aft,” “fore,” “vertical,”“horizontal,” “proximal,” “distal,” and the like are used forconvenience and are not intended to imply, for example, any particularfixed location, orientation, or direction. Instead, such labels are usedto reflect, for example, relative location, orientation, or directions.It should also be understood that the singular forms of “a,” “an,” and“the” include plural references unless the context clearly dictatesotherwise.

Disks of a hard disk drive (“HDD”), such as that of FIG. 1 describedherein below, may be rotated at high speeds by means of an electricmotor including a spindle assembly mounted on a base of a housing. Suchelectric motors include a stator assembly including a number of statorteeth, each extending from a yoke. Each stator tooth of the number ofstator teeth supports a field coil that may be energized to polarize thefield coil. Such electric motors further include one or more permanentmagnets disposed adjacent to the number of stator teeth. As the numberof field coils disposed on the number of stator teeth are energized inalternating polarity, the magnetic attraction or repulsion of a fieldcoil to an adjacent permanent magnet causes the spindle, including ahub, of the spindle motor assembly to rotate, thereby rotating the disksfor read/write operations by one or more read-write heads.

Various means may be used to manufacture motor parts and correspondingstructures using thinner materials and smaller size. For example, a HDDmay have a relatively thin base with a relatively heavy magnet in onecorner and a disk stack in the middle with a pivot between the diskstack and the heavy magnet. The properties of the magnet and theinertial properties of the spinning disk stack may create a balance toallow the pivot in between to stay aligned with the disk and preventtilting with respect to the disk stack. During operation of the HDD,each respective component of the HDD may have respective movementproperties (e.g., vibration). Such movement properties can haveundesirable effects including resonant vibrations, shock response, andacoustical issues.

On the other hand and according to embodiments described herein, thevarious movement properties of components within a device may beadjusted based on the shape of a particular component, the location, andthe connection or attachment points of the components. The adjustment ofthe movement properties of the components allows the movement propertiesto be tuned or brought within an acceptable range. For example, thestiffness, damping, vibration control, and response of HDD componentsmay be adjusted. In some embodiments, the location of HDD components isadjusted to change the overall movement properties of the overall HDD(e.g., vibration response).

In various embodiments, HDD components are coupled together (e.g.,glued, screwed, etc.) to adjust the movement properties of the HDDcomponents (e.g., overall movement properties of the HDD). In someembodiments, HDD components may be coupled on top and bottom to a baseand cover, respectively, thereby adjusting the movement properties ofthe HDD components. In various embodiments, additional components (e.g.,structural, dummy, or imitation components) are added to the HDD toadjust the movement properties of the HDD. Some embodiments areconfigured to rearrange each of a plurality of components and therespective connections of the plurality of components to controlvibration (e.g., by increasing stiffness, damping, and vibrationcontrol).

FIG. 1 provides a plan view of a number of the components in a hard diskdrive 100, including a printed circuit board assembly (PCBa) attached toa base, according to one aspect of the present embodiments. In order tobetter describe embodiments, a few of the components in the hard diskdrive 100 will be briefly described.

Hard disk drive 100 may include a housing assembly including a cover 102that mates with a base deck having a frame 103 and a floor or base 104,which housing assembly provides a protective space for various hard diskdrive components. The hard disk drive 100 includes one or more datastorage disks 106 of computer-readable data storage media. Typically,both of the major surfaces of each data storage disk 106 include anumber of concentrically disposed tracks for data storage purposes. Eachdata storage disk 106 is mounted on a hub 108, which in turn isrotatably interconnected with the base deck and/or cover 102. One ormore data storage disks 106 may be mounted in vertically spaced andparallel relation on the hub 108. A spindle motor assembly 110 rotatesthe data storage disks 106.

The hard disk drive 100 also includes an actuator arm assembly 112 thatpivots about a pivot bearing 114, which in turn is rotatably supportedby the base deck and/or cover 102. The actuator arm assembly 112includes one or more individual rigid actuator arms 116 that extend outfrom near the pivot bearing 114. Multiple actuator arms 116 may bedisposed in vertically spaced relation, with one actuator arm 116 beingprovided for each major data storage surface of each data storage disk106 of the hard disk drive 100. Movement of the actuator arm assembly112 is provided by an actuator arm drive assembly, such as a voice coilmotor 118 or the like. The voice coil motor 118 is a magnetic assemblythat controls the operation of the actuator arm assembly 112 under thedirection of control electronics 120. The control electronics or printcircuit board assembly (PCBa) 120 may include a number of integratedcircuits 122 coupled to a printed circuit board (PCB) 124. The controlelectronics 120 may be coupled to the voice coil motor assembly 118, aslider 126, or the spindle motor assembly 110 using interconnects thatcan include pins, cables, or wires (not shown).

A load beam or suspension 128 is attached to the free end of eachactuator arm 116 and cantilevers therefrom. Typically, the suspension128 is biased generally toward its corresponding data storage disk 106by a spring-like force. The slider 126 is disposed at or near the freeend of each suspension 128. What is commonly referred to as theread-write head (e.g., transducer) is appropriately mounted as a headunit (not shown) under the slider 126 and is used in hard disk driveread/write operations.

The head unit under the slider 126 is connected to a preamplifier 130,which is interconnected with the control electronics 120 of the harddisk drive 100 by a flex cable 132 that is typically mounted on theactuator arm assembly 112. Signals are exchanged between the head unitand its corresponding data storage disk 106 for hard disk driveread/write operations. In this regard, the voice coil motor 118 isutilized to pivot the actuator arm assembly 112 to simultaneously movethe slider 126 along a path 134 and across the corresponding datastorage disk 106 to position the head unit at the appropriate positionon the data storage disk 106 for hard disk drive read/write operations.Various embodiments for adjusting the stiffness, damping, vibrationcontrol, and response of HDD components will now be described in furtherdetail.

In an embodiment, frame 103 may be configured to provide stiffnessaround the perimeter of hard disk drive 100. The pivot rotational axismay be tied to or between cover 102 and base 104. As a result, spansbetween the pivot attach area and frame 103 may experience increaseddeflection during vibration or shock of hard disk drive 100 (e.g.,during the operation of hard disk drive 100). Embodiments are configuredto locate and connect components into such spans thereby increasingstiffness and damping thereby reducing the undesirable effects ofvibration and shock.

PCBa 120 may be linked with base 104 to improve stiffness. In someembodiments, PCBa 120 includes optional attachment points 140-142.Attachment points 140-142 allow PCBa 120 to be attached to floor or base104. In some embodiments, attachment points 140-142 allow PCBa 120 to beadhered (e.g. glued, screwed, etc.) to base 104 thereby increasingstiffness, damping, and/or vibration response of base 104. PCBa 120 maybe attached at a location where deflection is expected to or does infact occur. In some embodiments, PCBa 120 is connected to asubstantially middle portion of base 104. In various embodiments,attachment points 140-142 include structures configured for attachingstructures to base 104 and/or cover 102. In some embodiments, base 104includes steel (e.g., stamped steel) and the attachment of PCBa 120 tobase 104 increases the stiffness of the steel.

An additional component may be connected to cover 102 to improvevibration control. In some embodiments, a component may be added toimprove performance (e.g., stiffness) while the component is without anyother function. In various embodiments, hard disk drive 100 includesoptional structure 144 (e.g., a pole) configured to attach voice coilmotor 118 to cover 102. Structure 144 may be shaped and positioned toincrease the overall stiffness, damping, and/or vibration response ofhard disk drive 100.

FIG. 2 provides a plan view of a hard disk drive including a PCBalaminated to a base, according to one aspect of the present embodiments.Elements of hard disk drive 200 having the same reference numerals ashard disk drive 100 may perform substantially similar functions asdescribed herein with respect to hard disk drive 100. Hard disk drive200 includes laminate 150. Laminate 150 attaches PCBa 120 to base 104thereby increasing the stiffness, damping, and vibration control of harddisk drive 200. In some embodiments, laminate 150 is formed bylaminating PCBa 120 to base 104. In various embodiments, base 104includes a flat portion and PCBa 120 is laminated to base 104 with, forexample, a viscoelastic damping laminate configured to dampen vibration.

FIG. 3 provides a plan view of a hard disk drive including a connectorblock coupled to a cover, according to one aspect of the presentembodiments. Elements of hard disk drive 300 having the same referencenumerals as hard disk drive 100 may perform substantially similarfunctions as described herein with respect to hard disk drive 100. Harddisk drive 300 includes connector block 160. In some embodiments,connector block 160 communicatively connects PCBa 120 to drive connector138. Connector block 160 may communicatively connect PCBa 120 to driveconnector 138 through base 104. In some embodiments, connector block 160is attached to base 104 and extends upward from PCBa 120 and attaches tocover 102 thereby increasing stiffness, damping, and vibration controlof hard disk drive 300. Connector block 160 may further be attached tocover 102 by tape that surrounds a portion of connector 160 in contactwith cover 102. In further embodiments, connector block 160 may beselectively positioned within the hard disk drive 300 in order toselectively control stiffness damping, and vibration.

FIG. 4 provides a plan view of a hard disk drive including a firstcomponent attached to a second component, according to one aspect of thepresent embodiments. Elements of hard disk drive 400 having the samereference numerals as hard disk drive 100 may perform substantiallysimilar functions as described herein with respect to hard disk drive100. In some embodiments, actuator arm assembly 112 pivots about pivotpoint 172. Hard disk drive 400 may include structure 170 that connectspivot point 172 and spindle motor assembly 110. Structure 170 may beconfigured to attach pivot point 172 to spindle motor assembly 110 viaglue, screw, or other attaching structure or component. In someembodiments, the connecting of pivot point 172 and spindle motorassembly 110 by structure 170 thereby provides increased stiffness,damping, and vibration control to hard disk drive 400. The attaching ofpivot point 172 to spindle motor assembly 110 provides added stiffnessand damping as compared to when pivot point 172 and spindle motorassembly 110 are not attached together.

FIG. 5 provides a plan view of a hard disk drive including an additionalcomponent configured to reduce vibration of the hard disk drive,according to one aspect of the present embodiments. Elements of harddisk drive 500 having the same reference numerals as hard disk drive 100may perform substantially similar functions as described herein withrespect to hard disk drive 100. In some embodiments, hard disk drive 500includes (optional) structures 180-184. In some embodiments, structures180-184 may be imitation components (e.g., primarily structural and/ornon-functional) or functional components. Structures 180-184 may havevarious properties including thermally conductive properties,desiccation properties (e.g., silica type functions), or filterproperties (e.g., for gas or moisture). In various embodiments,structures 180-184 may be created by injecting a material configured toexpand into an open space within hard disk drive 150. In someembodiments, structures 180-184 may be made of an injected materialconfigured for thermal transmission and attach PCBa 120 to base 104and/or cover 102. In various embodiments, structures 180-184 may be madeof a substantially rigid material including, but not limited to, steel,brass, copper, and/or bronze. Structures 180-184 may be selectivelyconnected to base 104, cover 102, or both thereby providing increasedstiffness, damping, and vibration control to hard disk drive 500.

FIG. 6 provides a side view of a hard disk drive including a structurefor adjusting vibration, according to one aspect of the presentembodiments. Elements of hard disk drive 600 having the same referencenumerals as hard disk drive 100 may perform substantially similarfunctions as described herein with respect to hard disk drive 100. Harddisk drive 600 includes cover 102, base 104, frame 103, and structure608. In some embodiments, structure 608 is connected to base 104 and/orcover 102 to increase stiffness, damping, and/or vibration control ofhard disk drive 600. In some embodiments, an upper portion 610 ofstructure 608 includes a rough or coarse surface that forms a frictionattachment with cover 102 thereby countering axial pressure or shearing.The friction attachment with cover 102 may thereby selectively increasethe stiffness, damping, and/or vibration control of hard disk drive 600.

The attachment of a component to the top and bottom of the device allowsfor the filling of otherwise dead space and creating a strongerstructure. In some embodiments, cover 102 is thinner than base 104 andcomponents may be attached to cover 102 and base 104 to distributestiffness more evenly between cover 102 and base 104. In variousembodiments, structure 608 may be a dummy or imitation componentconfigured to maintain the relative location of cover 102 and base 104when pressure that creates shear or bending between cover 102 and base104 is created (e.g., during operation of a HDD).

FIG. 7 shows an exemplary flow diagram for determining a componentconfiguration, according to one aspect of the present embodiments.Flowchart 700 depicts a process for determining locations and connectionconfigurations of components in a device (e.g., a device including anelectric motor assembly) to reduce vibration by adjusting stiffness,damping, and vibration response of the device. Flowchart 700 may be usedto intelligently attach various components within a device or apparatusto improve the overall performance of the device (e.g., by increasingstiffness, damping, and vibration control). Portions of flowchart 700may be performed multiple times in order to achieve increasing optimalconfigurations (e.g., converge to a respective location and respectiveattachment configuration) for each the components of a device.

At block 702, a first location corresponding to a first component of anapparatus is accessed. The apparatus may further include an electricmotor assembly. In some embodiments, a datastore (e.g., database, datafile, etc.) including location and connection information aboutcomponents of a device (e.g., including an electric motor assembly suchas a hard disk drive) may be accessed. In various embodiments, thelocation and connection information may be accessed by a simulator.

At block 704, the apparatus or device is operated. In some embodiments,a simulation (e.g., via a modeling tool configured for simulatedannealing) is performed to simulate operation of the apparatus. Thesimulating may include determining a respective motion of each of aplurality of respective components of the apparatus. In variousembodiments, the apparatus is operated and various sensors are used todetect a respective motion of each of the components of the apparatus.The motion and mode shapes of each component may be determined based onthe operation (e.g., simulated or actual operation of the device).

At block 706, a second location corresponding to the first component isdetermined. The determination of a second location may be based onreducing vibration of a device (e.g., during operation of a hard diskdrive). In some embodiments, properties of the operation of a device(e.g., HDD) including stiffness, vibration, etc., are considered indetermining specific attachments or connections (e.g., to a top coverand a bottom portion of a device). In some embodiments, location ofvarious components and the topology of the components is analyzed andcompared to determine a particular topology to provide a desiredperformance effect (e.g., improved stiffness, damping, and vibrationresponse). In some embodiments, dummy or imitation components may beused to balance a device and to determine a particular topology withdesired performance. In various embodiments, the location and connectionof a component as well as a subset thereof may be used in determining aparticular topology.

The second location may be determined based on locating a mode shapethat is undesirable and determining a location that will disrupt orbreak the mode shape lines between modes shapes. The location may bedetermined based on locating a maximum deflection or an acousticalproblem, examining the modal analysis (e.g., including the shape of thedeflection where a frequency of interest is and the maximum deflection)and connecting a component (e.g., PCBa 120) at that location to dampenthe movement.

At block 708, a connection or attachment configuration of the firstcomponent is determined. The connection configuration may includeconnecting the first component to a second component. In someembodiments, the attachment configuration may include an attachment ofthe first component to a base and/or a cover. The attachmentconfiguration may include an attachment of a pivot point to a motorattachment point to increase stiffness and damping. In some embodiments,the attachment configuration includes gluing, screwing, or laminating afirst component to a second component. In various embodiments, a firstcomponent may be attached via friction to a second component.

At block 710, whether an additional component is to be added isdetermined. In some embodiments, an additional component (e.g., astructural component without other function) may be added based ondetermining that an additional component will reduce vibration (e.g., byincreasing stiffness, damping, or vibration control). Block 702 may thenbe performed if additional analysis of components is desired.

As such, provided herein is an apparatus, including an electric motor, abottom portion, and a top portion. The bottom portion or the top portionis connected to the electric motor. The apparatus further includes afirst component connected to the bottom portion at a first location andconnected to the top portion at a second location. A first connection ofthe first component at a first location is configured to increasestiffness. A second connection of the first component at a secondlocation is also configured to increase stiffness. In some embodiments,the bottom portion is a base component of the apparatus and the topportion is a cover component of the apparatus.

The first location and second location may be configured to increasedamping of the apparatus and reduce vibration. Furthermore, the firstconnection and the second connection may be configured to increasedamping or reduce vibration. In some embodiments, the first component isconnected to a second component and the connection of the firstcomponent to the second component increases the stiffness of theapparatus. In various embodiments, the first component is an imitationcomponent. The first connection may be formed by an attachment processselected from the group consisting of gluing, screwing, and laminating.In some embodiments, the first component is connected to the top portionvia a friction connection.

Also provided herein is an apparatus, including a first component and asecond component. The second component is located at a first positionand includes a first connection to the first component. The firstposition and the first connection are configured to stiffen an electricmotor assembly. The first position and the first connection to thesecond component are configured to increase stiffness of the apparatus.In various embodiments, the first position and the first connection tothe second component are further configured to reduce vibration andincrease damping of the apparatus. In some embodiments, the secondcomponent is a cover component.

In an embodiment, the first component may have a second connection to abase component. In various embodiments, the second component is afunctional component of the apparatus. In some embodiments, the secondcomponent includes a portion having a property selected from the groupconsisting of thermal conductance and desiccation. The first componentmay be a printed circuit board assembly (PCBa). In some embodiments, thefirst connection may be selected from the group consisting of glue,screw, and laminate.

Also provided herein is an apparatus, including a base component and acover component attached to the base component. The cover component maybe above the base component. The apparatus further includes an electricmotor assembly and means for increasing vibration damping of theapparatus. A first portion of electric motor assembly is configured torotate in between the base component and the cover component. The meansfor increasing vibration damping of the apparatus is connected to thebase component and the cover component. The means for increasingvibration damping of the apparatus may be a component configuration thatincreases vibration damping of the apparatus.

In some embodiments, the means for increasing vibration damping of theapparatus is a structural component. In various embodiments, the meansfor increasing vibration damping of the apparatus is further configuredto increase stiffness and vibration control. The means for increasingvibration damping of the apparatus may be further connected to theelectric motor assembly. The connection of the means for increasingvibration damping of the apparatus to the electric motor assemblyincreases stiffness. In some embodiments, the means for increasingvibration damping of the apparatus is configured to distribute stiffnessbetween the base component and the cover component.

While embodiments have been described and/or illustrated by means ofexamples, and while these embodiments and/or examples have beendescribed in considerable detail, it is not the intention of theapplicant(s) to restrict or in any way limit the scope of theembodiments to such detail. Additional adaptations and/or modificationsof the embodiments may readily appear in light of the describedembodiments, and, in its broader aspects, the embodiments may encompassthese adaptations and/or modifications. Accordingly, departures may bemade from the foregoing embodiments and/or examples without departingfrom the scope of the embodiments. The implementations described aboveand other implementations are within the scope of the following claims.

What is claimed is:
 1. An apparatus comprising: an electric motor; abottom drive portion and a top drive portion, wherein one or more of thebottom drive portion or the top drive portion is connected to theelectric motor; a first component connected to the bottom drive portionat a first location and connected to the top drive portion at a secondlocation; a first connection of the first component at the firstlocation configured to substantially stiffen the electric motor withrespect to at least one of the bottom drive portion or the top driveportion; and a second connection of the first component at the secondlocation configured to substantially stiffen the electric motor withrespect to at least one of the bottom drive portion or the top driveportion.
 2. The apparatus of claim 1, wherein the bottom drive portionis a base component and the top drive portion is a cover component. 3.The apparatus of claim 1, wherein connection of the first component tothe top drive portion and to the bottom drive portion is configured tosubstantially dampen vibration of the electric motor.
 4. The apparatusof claim 1, wherein the first component is connected to a secondcomponent, and wherein the connection of the first component to thesecond component is configured to substantially stiffen the electricmotor with respect to at least one of the bottom drive portion or thetop drive portion.
 5. The apparatus of claim 1, wherein the firstcomponent is an imitation component.
 6. The apparatus of claim 1,wherein the first connection is formed by gluing, screwing, orlaminating.
 7. The apparatus of claim 1, wherein the first component isconnected to the top drive portion via a friction connection.
 8. Anapparatus comprising: a first component that is separate from a basecomponent and a cover component; and a second component selected from agroup consisting of the base component and the cover component, whereinthe second component is located at a first position and includes a firstconnection to the first component, wherein the first component connectedto the second component at the first position via the first connectionis configured to stiffen an electric motor assembly.
 9. The apparatus ofclaim 8, wherein connection of the first component to the secondcomponent at the first position via the first connection is configuredto substantially dampen vibration of the apparatus.
 10. The apparatus ofclaim 8, wherein the second component is the cover component.
 11. Theapparatus of claim 8, wherein the first component has a secondconnection to the base component.
 12. The apparatus of claim 8, whereinthe second component is a functional component of the apparatus.
 13. Theapparatus of claim 8, wherein the second component includes a thermalconductance property or a desiccation property.
 14. The apparatus ofclaim 8, wherein the first component is a printed circuit boardassembly.
 15. The apparatus of claim 8, wherein the first connectionincludes glue, screw, or laminate.
 16. An apparatus comprising: a basecomponent; a cover component coupled to the base component; an electricmotor assembly, wherein a first portion of electric motor assembly isconfigured to rotate with respect to the base component; and a means fordamping vibration of the apparatus, wherein the means for dampingvibration of the apparatus is directly connected to the base componentand the cover component.
 17. The apparatus of claim 16, wherein themeans for damping vibration of the apparatus is a structural component.18. The apparatus of claim 16, wherein the means for damping vibrationof the apparatus is further configured to substantially stiffen theelectric motor assembly and control vibration of the electric motorassembly.
 19. The apparatus of claim 16, wherein the means for dampingvibration of the apparatus is further connected to the electric motorassembly.
 20. The apparatus of claim 16, wherein the means for dampingvibration of the apparatus is configured to distribute stiffness betweenthe base component and the cover component.